Pneumatic hammer



July 22 1930. w, WALSH 1,771,238

PNEUMATI G HAMMER Filed Dec. 27, 1926 2 Sheets-Sheet 1 Patented July 22, 1 930 WILLIAM FRANCIS WALSH, OF MCGILL, NEVADA- V rNnUMA'rIo HAMMER Appl i cationfiled December 27, 1926. Serial No. 157,392. I,

My invention relates'to new and useful improvements in pneumatic or air hammers and has for its principal object the provision of such a device which is relatively simple in construction, light, and'has a relatively few movable parts.

Another object of the inventionresides in the provision of a hammer of the character described in which the valve controlling the passage of'air is operable by the movement of the reciprocable piston carried by the barrel.

Another object consists in the provision of a cushion or abutment for the piston, up on its upward movement, to prevent jar and to eliminate recoil. i

A further object of the invention resides in the provision of a muflier for the air issuing from the exhaust ports.

With the above andother objects in view, which will appear as the description proceeds, my invention consists in the novel details of construction, and arrangement of parts, described in the following specification and illustrated in the accompanying drawings, and while I have illustrated and described the preferred embodiments of the invention, as they now appear to me, it will be understood that such changes may be made as will fall within the scope of the appended claims.

In the drawings:

Fig. 1 is a longitudinal section with parts shown in elevation.

Fig. 1 is a bottom plan of the lock nut and mufiier. v

Fig. 2 is a fragmental enlarged longitudinal section of the upper part of the piston barrel and valve chamber. I

Fig. 3 is a section on the line 3-3 of Fig.

2 looking in the direction of the arrows.

Fig. 4 is a section on the line 44 of Fig.

2 looking in the direction of the arrows.

5 is a section on the line 55 of Fig.

2 looking in the direction of the arrows.

Fig. 6 is a section on the line 66 of Fig. 2 looking in the direction of the arrows; and Fig. 7 is a section on the line 7-'-7 of Fig.

1 looking in the direction of the arrows.

In the drawing 1 indicates a barrel or cylinder having the longitudinally extending central chamber 2 in which the piston?) is adapted to reciprocate. Received in the lower or outer end of the chamber 3 is the ferrule 4 having the outwardly extending flange 5 which overlies the end of the barrel 1 as shown more particularly in Fig. 1 of the drawings. A chisel or othersuitable instrument is'carried by the ferrule 4, the upper end or shank of the instrument passing through the ferrule and beyond the inner end thereof to be engaged by the piston 3 for imparting'a blow thereto. 1

The upper or inner end of the barrel 1 is exteriorly. threaded as shown at 7 to receive the interiorly threaded cap or housing 8 having the handle 9 formed integral therewith. A lock nut 8 also engages the threads? and the lower end of the cap or housing 8, this nut having a depending portion 9 with an inwardly extending notched flange 9". A passage 10 is formed in the handle 9 and communicates with the cap or housing 8. The outer end ofthe handle lO is formed with an interiorly threaded recess toreceive the exteriorly threaded bushing 11, having the interiorly threaded bore 12 for the connection of an air hose or the like. Extending through the handle 9 and intersecting the passage 10 i is the valve housing or sleeve 13 having the openings 1 1 and 15 communicating with the passage. Operable in the sleeve or housing 13 is the slidable valve 16 normally held'in position to close the openings 14 and 15 by means of the coiled spring 17, the tension of the spring 17 being adjusted by means of $5 the screw 18 which engages the outer end of the spring. An outwardly extending flange 19 is formed on the outer end of the sleeve or housing 13 as shown more particularly'in Fig. 1. The valve 16 has the reduced extension 20 which passes through an opening 21 in the inner end of the sleeve or housing 13 and is adapted'to be engaged by the trigger 22 pivotally connected to the handle at 23. As will be seen by reference to Fig. 1 the trigger 22 extends parallel with the handle 9 and in position to be readily grasped by the operator. When the trigger is raised or pulled towards the handle the valve 16is forced inwardly of the sleeve or housing 13, 00

against the tension of the spring 17, to open the openings 14 and 15 to allow passage of air therethrough.

The barrel 1 is formed with the longitudinally extending bores or passages 24 and 25 leading from the upper end thereof. The upper end of the bore or passage 25 is normally closed by means of the threaded plug 26. Extending from the outer surface of the barrel 1, intersecting the passage 25, and communicating with the chamber 2, are the openings 27, 28 and 29, the outer ends of the openings being closed by the plugs 30, 31 and 32, respectively. Intermediate the ends of the bore or passage 25 is the exhaust port Extending from the outer surface of the barrel 1, intersecting the bore or passage 24, and communicating with the chamber 2, below the lowermost position of the piston 3, is the opening 34, the outer end of which is normally closed by means or" the plug 35. Extending from opposite sides of the barrel 1, and communicating with the chamber 2, above the lowermost position of the piston 3 are the vertically spaced exhaust ports 36 and 37. The depending portion 9 of the lock nut 8 overlies the ports 33, and 37 and acts as a muflier as well as to keep dirt out of the ports.

Seated on the upper or inner end of the barrel 1, and enclosed by the cap or housing 8 is the valve chamber or casing 38 of less diameter than the interior diameter of the cap or housing 8 thereby leaving a passage around the chamber or casing 38 for the circulation of air in a manner and for a purpose to be presently described. An outwardly extending flange 39 is formed on the lower or inner end of the chamber or casing 38 and is engaged by the shoulder 40 formed interiorly of the cap or housing 8 for properly positioning the chamber or casing 38 relative to the barrel 1. The chamber or casing 38 is provided with the longitudinally extending central passage 41 which is restricted at its inner or lower end to form the valve seat 42 for the slidable valve 43 operable within the passage 41. The valve is provided on its inner or lower end with the extension 44 which extends through the opening 45 beof the barrel 1.

Extending outwardly from and communicating with the central passage 41 of the valve chamber or housing 38 are the passages 48 and 49, the passage 48 communicating with the passage 50 which is in alignment and communicates with the passage 24 in the barrel 1. The passage 49 communicates with the passage 51 which is in alignment with the passage 25 in the barrel 1 and communicates with the circumferentially extending groove 52 formed in the inner or lower face of the valve chamber or housing 38. The passage 50 also communicates with the groove 52. Extending inwardly from the outer surface of the valve chamber or housing 38, and

communicating with the central passage 41 are a plurality of circum'rerentially spaced openings 53.

A cushion or abutment plate 54 is positioned at the top 01 the cap or housing 8 and is adapted to be engaged by the valve 43 when the same is raised. This plate has the th readed extension or shank 55 which extends through the top of the cap or housing 8 and receives the nut 56 as more particularly illustrated in Figs. 1 and 2 of the drawings. The inner surface or face of the plate 54 is formed with a plurality of recesses 57 for a purpose to be later described.

Having described the detail construction I will now endeavor to more clearly bring out the mode of operation. WVith the parts shown in Fig. 1, when it is desired to operate the hammer the operator takes hold of the handle 9 and with his fingers engages the trigger 22 for operating the valve 16. When the valve 16 is pushed inwardly of its chamber or housing the openings '14 and 15 are uncovered and air passes through the passage 10 in the handle, the openings 14 and 15, and into the cap or housing 8 to be circulated as shown by the arrows in Fig. 1. The valve 43 is normally positioned upon its seat 42 cutting off the passage of any air through the openings With the valve in such position air enters the central opening 41 of the valve chamber or housing 38 and goes through the passages 43, 49, 50 and 51 from which it passes to the passage 24 and is discharged beneath the lower end 01" the piston 3 through the opening 34. The discharge of air raises the piston 3 and the piston engages with the extension 44 of the valve 43 and raises the same to cut off the supply of air to the passages 48 and 49 and opens the passages 53. This allows the air to enter the openings or passages 53 and to pass through the opening 45 and be discharged against the upper r inner end of the piston 3 to lower the same and to contact with the end of the shank of the instrument for imparting a blow thereto. As the piston is lowered the valve 43 returns to its normal or original position. On the down stroke of the piston air is exhausted through the openings 36 and 37 and on the up stroke of the piston air is exhausted through the openings 27, 28 and 29, passage 25, and exhaust port It will be understood that air cannot pass from the passage 51, in the valve chamber or housing 38, into plurality the passage 25, of the barrel, because of the plug 26 inserted in the upper or inner end Oil the passage 25. Air entering the passage 51 will circulate around the circumferentially extending groove 52 and be discharged into the passage 24 of the barrel; As the valve 43 is raised it will engage with the plate 54 and as the upper surface of the valve and the inner surface of the plate are each provided with a of recesses a cushioning action is obtained to overcome jar and to eliminate recoil. As previously stated the depending portion 9 of the lock nut 8 acts as a mufiler for air discharged from the ports 33, 36 and I Wish to lay particular stress on the sim plicity of construction and to the fact that l have only three movable parts, these being the valve 16, the valve 43, and the piston 3.

i With my construction the operator will not openings, to alternately admit tire and the hammer is more easily handled than is the old form of hammer. While illustrated with a chisel as the instrument used it will be understood that different forms of instruments might be used, for various di:tferent purposes.

Having fully described my invention what I claim as new and desire to secure by Letters Patent is:

1. A device of the character described including a barrel having air passages therein, an instrument car -ied by the barrel, a piston operable in the barrel for imparting a blow to the instrument, a valve chamber received on one end of the barrel, said valve chamber having a vertically extending central opening restricted adjacent its lower endto form a valve seat, side openings communicating therewith intermediate the ends and vertically extending passages communicating therewith adjacent the upper end and with one of the air passages in the barrel, a valve operable in the chamber and normally received on the valve seat, and a projection formed on the valve and extending below the chamber to be engaged by the piston to raise the valve from its seat, said valve when in one position cutting oil the top opening and air passages while in another position cutting off the side air under pres sure to opposite sides of the piston.

2. A device of the character described including a barrel having air passages therein, an instrument carried by the barrel, a piston operable in the barrel for imparting a blow to the instrument, a valve chamber received on one end of the barrel, said valve chamber having a vertically extending central opening restricted adjacent its lower end to form a valve seat, side openings communicating therewith intermediate the ends and vertically extending passages communicating therewith adjacent the upper end and with one of the air passages in the barrel, a valve operable in the chamber and normally received on the valve seat to cut oil the side openings but allow the flow of air under pressure through the vertically extending passages in the chamber and one of the passages in the barrel to engage the bottom end of the piston and raise the same in the barrel, and a projection formed on the valve and extending below thev chamber to be engaged by the piston the same is raised to move the valve valve when from its seat to cut oil the flow of air to the valve chamber passages and barrel passage 

